This invention relates generally to a character recognition system, and more particularly, but not by way of limitation, to a character recognition system for bank checks and the like using optical character recognition, i.e. OCR, and magnetic ink character recognition, i.e. MICR, techniques to read a plurality of characters on the checks and logically edit the character codes.
Bank checks and other documents are often imprinted with magnetic ink to form characters which can be read electronically using either MICR or OCR techniques or both. Reader/sorter equipment is employed to read the characters on the documents and sort the documents in a prescribed order dependent on the information obtained in reading each of the characters. If a character cannot be read for one reason or another, the document is rejected and read by an equipment operator. However, since reader/sorter equipment ordinarily reads and sorts a large number of documents at a high rate of speed, it is necessary to maintain the rejection rate as low as possible to maintain overall system efficiency.
There are numerous reasons why characters are misread or rejected when read either magnetically or optically. For example, non-uniform magnetic particle distribution within the ink area may cause erroneous reading of a character when read magnetically. Also, bank stamps, marks, dirt and other extraneous visual printing on the document may cause errors in reading the character optically. Blurred characters may be misread or rejected both optically and magnetically depending on the extent and nature of the blur.
Heretofore prior art patents have disclosed systems to read characters both magnetically and optically. The results of the reading is compared and the probable character is logically selected based upon the results of the reading and compare. Examples of these systems may be found in U.S. Pat. No. 3,764,978 to Tyburski, et al; U.S. Pat. No. 3,876,981 to Welch; and U.S. Pat. No. 3,949,363 to Holm. Also U.S. Pat. No. 3,764,980 to Dansac, et al, while employing OCR techniques, provides redundant recognition to reduce rejection of the reading.
One significant problem associated with the prior art recognition systems, and particularly those systems employing redundant character recognition, is that prior techniques have operated on the assumption that there is an exact correspondence between the number of characters read in one mode, for example MICR and the number of characters read in another mode, for example OCR. However, it has been found that the presence of extraneous matter on a document, i.e. marks, dirt and non-magnetic ink, the latter occurring from endorsement stamps, hand-written signatures, printed check backgrounds, etc. can cause the OCR reader to sense extraneous characters not truly present in the data to be read. Hence a principal reason for failure of the prior redundant character recognition systems arose simply from the fact that there were more characters read from the OCR reader than by the MICR reader.
Another problem with prior art redundant character recognition systems resulted from the fact that as each character was read in the two or more modes, the recognition circuitry would select the probable results for inclusion in the final output. Thus, if a line of characters are read, character recognition is accomplished on each character independently of the result accomplished on adjacent characters. A reject of one character read will reject the entire document. However, circumstances may exist that certain of the characters may be logically derived from adjacent characters so that rejection of the reading of one character need not cause the entire document to be rejected.
The invention described herein recognizes the above problems of the prior art character recognition systems and solves these problems accordingly.